Visual exposure indicating system

ABSTRACT

A film cassette includes a cassette body, a film spool onto which can be wound a strip of film drive disk coupled directly to the film spool, and an indicator flex disk that includes a film status indicator tab whose position relative to a window of the film cassette indicates the film exposure status. The position of the film status indicator tab is changed when the flex disk is moved into engagement with the drive disk and the film spool is rotated upon film movement. The film status indicator tab otherwise does not engage the drive disk and therefore does not change position. The cassette is particularly suited for operation with a photographic camera that includes a camera body, a loading chamber in the camera body that receives the film cassette, and a loading chamber cover having at least one movable indicator release pin that moves the flex disk into and out of engagement with the drive disk and thereby changes the position of the film status indicator tab. A camera controller determines the film status and controls the movement of the indicator release pin to selectively change the position of the film status indicator tab in accordance with the film status.

This application is a reissue application of U.S. Pat. No. 5,552,849,issued on Sep. 3 1996, based on U.S. Ser. No. 08/377,542, filed Jan. 23,1995. .Iaddend.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to systems that indicate the exposurestatus of photographic film and, more particularly, to camera and filmcassette systems that cooperate to visually indicate the exposure statusof the film cassette.

2. Description of the Related Art

Photographic cameras typically accept roll strips of photographic filmthat are exposed one frame at a time. Many cameras are designed toaccept rolls of film that are enclosed within a light-tight filmcontainer such as a cassette or a canister. A typical container is thefamiliar 35 mm format film. After the film container is received withinthe camera, the film is pulled out of the container and stretched acrossan exposure gate, where frames are exposed in sequence, one after theother. It can be desirable to interrupt the sequential exposure offrames of the film in mid-roll so that a camera user can rewind apartially exposed roll of film back into the light-tight container,remove the container from the camera, and temporarily store thecontainer. At a later time, the camera user can reload the interruptedcontainer back into the camera and then position the film atapproximately the next unexposed frame location, ready to resume picturetaking.

The mid-roll interrupt (MRI) operation has many advantages, primarilywhere a roll of film will not be completely exposed before it isdesirable to load a new roll of film. For example, by removing a filmstrip in mid-roll, it is possible to maintain the same subject matterfor an entire roll of exposures taken over time without discardingunexposed frames as the camera user changes to a new roll and a newphotographic subject. The MRI feature also permits changing amongdifferent film types during a continuous picture taking session withoutdiscarding large portions of unexposed film, such as might be desirableunder changing light conditions.

Some cameras provide an automatic mid-roll interrupt (MRI) function inwhich a partially exposed roll of film is automatically rewound into thefilm container when the MRI function is invoked and is automaticallypositioned at the next unexposed frame location upon being reloaded intothe camera. Film cassettes designed for use with automatic MRI-capablecameras often include relatively complex mechanisms to ensure thecassette remains light-tight, and often include a film parking mechanismthat prevents the roll strip of film from unravelling or unspoolingwithin the cassette. Any unspooling of the film would make it verydifficult to resume making exposures at the correct frame position. Filmparking mechanisms can be relatively complex, having mechanisms forlocking the spool and for positioning light-tight film cassette doors,and can require complex camera-cassette mechanical interfaces.

One problem that can be encountered with mid-roll interrupt operationsis that an already-exposed roll of film can be inadvertently loaded andexposed once again, creating double images and mining the film.Therefore, film cassettes intended for use in conjunction with mid-rollinterrupt operation also typically include a visual indication of thefilm status. In this way, a user is immediately informed of the filmcassette status and does not attempt to load a cassette containing filmthat was already exposed or processed. Typically, the visual indicationprovided by such cassettes distinguishes the film status as being eitherunexposed, partially exposed, fully exposed, or processed.

As noted above, the mechanical interfaces between an MRI-capable cameraand a film cassette can be relatively complex and costly. Both themechanical interface and the film cassette design can be even morecomplex and costly if operation with both MRI and non-MRI cameras is tobe supported and the visual exposure indication is to be provided Forexample, if a film cassette is to be compatible with non-MRI cameras,then the camera-film cassette combination must automatically omit anyvisual indication of the film being partially exposed, as that would bea non-operational mode.

From the discussion above, it should be apparent that there is a needfor a photographic camera and film cassette combination that providesthe convenience and flexibility of the MRI feature and also providesdual operation such that MRI and non-MRI cameras can be operated withMRI and non-MRI film cassettes, without the complexity and costassociated with conventional camera-cassette combinations. The presentinvention fulfills this need.

SUMMARY OF THE INVENTION

In accordance with the present invention, a film cassette includes acassette body, a film spool onto which can be wound a strip of film, adrive disk coupled directly to the film spool, and an indicator flexdisk that includes a film status indicator whose position relative to awindow of the film cassette indicates the film exposure status. The flexdisk is moved into engagement with the drive disk to change the positionof the film status indicator when the film spool is rotated upon filmmovement, thereby changing the indicated film exposure status. The flexdisk otherwise is not engaged with the drive disk, thereby maintainingthe position of the film status indicator in its current position evenwhen the film spool is rotated. In this way, changing the state of thefilm exposure status indicator is a function of moving the flex diskinto and out of engagement with the drive disk during film spoolmovement.

The cassette is particularly suited for operation with a photographiccamera that includes a camera body, a loading chamber in the camera bodythat receives the film cassette, and a loading chamber cover having atleast one indicator release that moves the flex disk into and out ofengagement with the drive disk and thereby changes the status of thefilm status indicator. A controller determines the film status andcontrols the movement of the indicator release to selectively change theposition of the film status indicator in accordance with the filmstatus. In a non-MRI camera, the indicator release does not permitselection of a film status indicator position that would falselyindicate a partially exposed roll of film. In an MRI-capable camera, therelease indicator permits selection of any one of the appropriate filmstatus indicators. Thus, the exposure status of the film is readilyperceived, without need for complicated film park mechanisms, and thefilm cassette can be used with both MRI capable cameras and non-MRIcameras.

Other features and advantages of the present invention should beapparent from the following description of the preferred embodiments,which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a camera constructed in accordance withthe present invention in an operational orientation.

FIG. 2 is a perspective view of the camera illustrated in FIG. 1 and afilm cassette constructed in accordance with the present invention withthe camera in a film loading position.

FIG. 3 is a perspective view of the film cassette illustrated in FIG. 2.

FIG. 4 is a cross-sectional view of the film cassette illustrated inFIG. 3.

FIG. 5 is an exploded view of the flex disk, driver disk, and film spoolof the film cassette illustrated in FIG. 3.

FIG. 6 is a cross-sectional view of the film cassette of FIG. 3 wheninstalled in a non-MRI camera with the loading chamber cover closed.

FIG. 7 is a cross-sectional view of the film cassette of FIG. 3 wheninstalled in a MRI-capable camera with the loading chamber cover closed.

FIG. 8 is a cross-sectional view of a portion of the camera illustratedin FIGS. 1 and 2 showing the loading chamber cover open.

FIG. 9 is a cross-sectional view of the camera illustrated in FIG. 5after a film cassette has been inserted into the camera, with theloading chamber cover open.

FIG. 10 is a cross-sectional view of the camera illustrated in FIG. 9after the loading chamber cover is closed.

FIG. 11 is a block diagram of the camera illustrated in FIGS. 1 and 2.

FIG. 12 is a flow diagram illustrating the operating steps followed bythe camera controller of the camera illustrated in FIGS. 1 and 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 2 show a camera/film cassette combination 10 constructed inaccordance with the invention in which a camera 12 provides a mid-rollinterrupt (MRI) feature. FIG. 1 is a frontal view that shows the camerain an operational orientation, ready for picture taking. A camera userviews a scene through a viewfinder 14 and activates a shutter to permitambient light to enter the camera through an objective lens 16. Anelectronic flash 18 provides supplemental illumination, if necessary forproper exposure. FIG. 2 shows the camera 12 inverted for film loadingwith a camera loading chamber cover 20 in an open condition to reveal aloading chamber 22 receiving a film cassette 24. The film cassette isshown more clearly in FIG. 3, which shows that an end plate 26 of thefilm cassette includes multiple film exposure status icons 28, each ofwhich is located near an indicator notch 30, or window, of the endplate. An exposure status indicator tab 32 carried within the filmcassette provides a visual exposure indicator (VEI) by moving to aparticular one of the indicator notches 30.

In particular, the exposure status tab 32 is sized such that it can beurged into any one of the indicator windows 30, engaging the window andlocking the tab in the window, and also can be urged out of engagement.The tab indicates the film status as corresponding to the status icon 28adjacent to the indicator window with which the tab is engaged.Photographic film is wound onto a spool 34 carried within the cassette24. As described more fully below, engagement of the tab 32 with thewindows is controlled such that the tab moves with the spool when theindicated film status is to be changed and otherwise remains fixed whilethe spool rotates.

When the indicator tab 32 is engaged with one of the windows 30,movement of the film spool 34 causes no movement of the tab andtherefore the film exposure status indicated by the tab does not change.To change the indicated film status, the tab must be pressed out ofengagement with the window. Rotation of the film spool will then causethe tab to move to another window. Thus, the indicated film exposurestatus is determined by controlling the movement of the tab 32. In thisway, complex film parking mechanisms are not needed to indicate theproper exposure status of the film.

In the preferred embodiment illustrated in FIG. 3, the film exposurestatus icons 28 include an "unexposed" icon 28a that indicates thecassette contains a fresh, unused roll of film, a "partially exposed"icon 28b, used with MRI cameras, that indicates one or more frames ofthe film have been exposed and other frames remain unexposed, a "fullyexposed" icon 28c that indicates all frames of the film have beenexposed, and a "processed" icon 28d that indicates the film in thecassette has been exposed and processed. In the case of a processedcassette, it is intended that the processed film will remain in rollform within the cassette. Using such a scheme, a user who desires, forexample, photographic prints from the roll will simply provide theprocessed cassette to a printer or photographic finsher, who willproduce prints from designated frames of the film.

Movement of the exposure status indicating tab 32 can be controlled suchthat the film cassette 24 is compatible with cameras that are equippedwith the MRI feature and also with those that are not so equipped In thecase of a non-MRI camera, the window 30 associated with the "partiallyexposed" icon 28b will not be used. That is, the tab 32 is not permittedto engage with the end plate window adjacent the partially exposed icon28c. In the preferred embodiment, the cassette includes a window 36 thatprovides a mechanical means of sensing the exposure status of thecassette. The mechanical status sensing means is not part of the visualexposure status system described herein.

Details of the cassette 24 construction are illustrated in thecross-section drawing of FIG. 4, which shows a length of photographicfilm 38 wound onto the film spool 34. FIG. 4 shows that the film spoolis supported within the cassette body 39 and that a driver disk 40 isdirectly coupled to the film spool, thereby comprising an outwardlyprojecting flange of the spool. Located axially between the driver disk40 and the cassette end plate 26 is a flex disk 42 that can be engagedand disengaged with the driver disk. One end of the film spool 34comprises a drive socket 44 that receives a driving pin of the cameraand the other end of the film spool comprises an idler socket 45. Asdescribed more completely below, the camera driving pin causes rotationof the film spool when the film is to be moved, which also rotates thedriver disk 40. If the flex disk 42 is engaged with the driver disk 40when the film spool moves, then the flex disk also rotates.

FIG. 4 illustrates that the indicator tab 32 projects outwardly from theflex disk toward the indicator windows 30 of the end plate 26. Theindicator tab provides a visual exposure indication by engaging with oneof the windows 30, thereby indicating the film status as correspondingto the associated film icon 28. More particularly, the flex disk 42 canrotate, and the indicator tab 32 can be moved to a different window,only when the indicator tab is pressed out of engagement. If theindicator tab extends into one of the windows, then the flex disk 42will be held in a fixed position, even while the driver disk 40 and filmspool 34 rotate.

Thus, the film cassette 24 is provided to a consumer with the indicatortab 32 positioned through the first window 30 adjacent the unexposedicon 28a. A camera designed to receive the film cassette includes amechanism for depressing the indicator tab out of the first indicatorwindow when the film is moved from the first exposure frame. In anon-MRI camera that does not provide the mid-roll interrupt feature, theindicator tab then is pressed out of engagement with the window for theunexposed icon 28a and is next permitted to enter the windowcorresponding to the fully exposed icon 28c.

In view of the cassette structure described above, either one of two tabchanging schemes can be used. After the initial loading of the filmcassette 24, an MRI camera permits the indicator tab 32 to enter thesecond indicating window, adjacent the partially exposed icon 28b. Ifthe camera user invokes the MRI feature, then the film is rewound intothe film cassette and engagement of the indicator tab 32 is controlledso there is no change in the position of the tab as the film is rewound.At the completion of rewinding, the camera user removes the filmcassette, which properly indicates the partially exposed status.

Alternatively, after the initial loading of the film cassette 24, theMRI camera 12 can immediately permit the indicator tab 32 to enter thethird indicating window corresponding to the fully exposed icon 28c. Ifthe MRI feature is not invoked, then no change in the indicator tabposition is necessary until the end of the film is reached. If thecamera user invokes the MRI feature before the end of the film isreached, the camera controls engagement of the indicator tab 32 topermit the tab to move back as the film 38 is rewound into the filmcassette and enter the second indicating window corresponding to thepartially exposed icon 28b. Once again, when the user removes the filmcassette from the camera the cassette will properly indicate thepartially exposed status.

Whether or not the camera provides the MRI feature, after the entirefilm has been exposed, the indicator tab 32 is released from its window30 and permitted to move with the last frame movement into the fullyexposed icon window 28c so the film cassette will indicate the fillyexposed status. As noted above, when the film is processed, the filmprocessor will cause the indicator tab 32 to be moved into the window 30for the processed icon 28d.

FIG. 5 is an exploded diagram that illustrates the relationship betweenthe film spool 34, the driver disk 40, and the flex disk 42. FIG. 5shows that the film spool has a ledge 46 that axially supports thedriver disk 40. A locating key 48 that projects upwardly from the spoolledge engages the driver disk, which has a keyed bottom circumferencethat is adapted to engage with the locating key. The spool locating keyand the driver disk cooperate to prevent relative movement between thedriver disk and the film spool. FIG. 5 also shows that the flex disk 42rests on the driver disk 40 and is axially supported thereon.

FIG. 5 shows that the indicator tab 32 is a projection from asubstantially planar flex disk feature 49 that extends outwardly fromthe circumference of the flex disk sufficiently that the flex diskfeature can be urged upwardly and downwardly relative to the plane ofthe flex disk. FIG. 5 also shows a drive pin 50 of the flex disk thatcomprises a projection from the flex disk feature 49 that extendingdownwardly away from the indicator tab 32. FIG. 5 further shows a driverfeature 52 of the driver disk 40 that comprises a projection thatextends outwardly from the circumference of the driver disk. Flexing ofthe flex disk feature 49 controls rotation of the flex disk bycontrolling engagement of the indicator tab 32 with the film statuswindows and contact between the drive pin 50 and the driver feature 52.

More particularly, if the indicator tab 32 is engaged in one of the filmstatus windows 30 when the film spool 34 is rotated, then the drive pin50 of the flex disk 42 is located away from the driver disk 40 withsufficient clearance so that the driver feature 52 passes by the drivepin as the driver disk rotates with the film spool. The driver disk 40thereby rotates independently of the flex disk 42, which does not move.Thus, the indicator tab 32 does not move and the indicated film exposurestatus does not change. This condition is illustrated in FIG. 4, whichshows the indicator tab 32 engaged with one of the windows 30 and thedrive pin 50 released from engagement with the driver disk drive feature52.

If, however, the indicator tab 32 is pressed out of engagement with thefilm status windows 30, then the flex disk feature 49 will be flexedaxially toward the driver disk 40 sufficiently so that the drive pin 50is moved to a position where it can contact the driver feature 52. Undersuch conditions, the drive pin interferes with passage of the driverfeature as the driver disk rotates with the film spool 34. The driverfeature thereby pushes against the drive pin and therefore the flex disk42 rotates with the driver disk 40 until the indicator tab 32 can engagewith another one of the film status windows 30. It should be apparentthat any camera that will change the indicated film exposure status musthave a mechanism for engaging and disengaging the indicator tab 32 fromthe film status windows 30.

As noted above, in a non-MRI camera, the partially exposed icon 28b isnot used. Therefore, if the camera 12 does not provide the MRI feature,then it will include a release pin that prevents the indicator tab 32from extending into the window 30 for the partially exposed icon 28b.FIG. 6 is a cross sectional illustration of the film cassette 24 in thenon-MRI camera, in which a release pin 60 of the camera is shownextending into the window 30 for the partially exposed icon 28billustrated in FIG. 3. The release pin is biased by a spring 61 of thecamera so that the pin extends into the film status window when the filmcassette is loaded and thereby prevents indication of the partiallyexposed status. That is, the release pin 60 is located in the camerasuch that it is aligned with the appropriate film status window. Aspring loaded idler pin 62 of the camera 12 is shown extending into theidler socket 45 of the film spool 34 to help locate the film spool andcassette properly in the camera loading chamber. The opposite end of thefilm spool is shown engaged with a camera driving pin 64 that is keyedto engage the film spool and rotate it.

In general, if the camera 12 is to control the film exposure statusindicated by the indicator tab 32, then the camera must have the abilityto selectively press the indicator tab out of the various indicatorwindows 30 of the film cassette 24. FIG. 7 is a cross sectionalrepresentation of the film cassette 24 located in such an MRI camera, inaccordance with the preferred embodiment FIG. 7 shows a movable releasepin 60 that can be selectively actuated to move into and out of the filmstatus window 30. Only one of a plurality of moveable release pins isillustrated in FIG. 7 for simplicity of illustration, but it should beunderstood that the camera 12 includes a similar release pin mechanismfor each of the film status windows 30 of the film cassette 24.

When a particular exposure status of the film is to be indicated, therelease pin corresponding to the window of the appropriate icon 28 isretracted so that the indicator tab 32 can extend into the correspondingwindow and indicate the desired status (as illustrated in FIG. 4). Allother release pins will be extended as illustrated in FIG. 7 so as toprevent the indicator tab from entering into their respective windows.FIG. 7 shows that the movable release pin 60 is moved by a solenoidactuator 74 to press the indicator tab 32 into and out of engagementwith the film status window 30 and move the drive pin 50 downwardly sothat it can contact the driver feature 52 of the driver disk 40. Thus,unlike the pin of FIG. 6 that was continuously urged by the spring 61,the pin of FIG. 7 is selectively moved back and forth by a solenoidactuator. The solenoid actuator typically comprises a magnetic coil thatcan move the pin 60 into the film status window 30 with an energizingcurrent. Reversing the polarity of the current serves to retract thepiston back into the coil. Other schemes for providing a release pin andits necessary movement to control the indicator tab will occur thoseskilled in the art.

In the preferred embodiment, the release pins are contained in theloading chamber cover FIG. 8 is a cross sectional illustration of thecamera 12 with the loading chamber cover 20 in the open position. A filmdriving pin 64 is shown extending into the loading chamber 22 and theidler pin 62 is shown extending from the chamber cover into the loadingchamber. FIG. 9 shows the camera after the film cassette 24 has beenloaded into the loading chamber. FIG. 9 illustrates the coupling or thedriving pin 64 into the film spool 34. Next, FIG. 10 shows the loadingchamber cover 20 in the closed position. FIG. 10 illustrates theengagement of the idler pin with the film spool and the engagement ofthe release pin 60 with the indicator tab 32 of the flex disk 42. Asnoted above, the camera includes a controller that moves the variousrelease pins appropriately to indicate the appropriate film status.

FIG. 11 is a block diagram of the MRI-equipped camera of the preferredembodiment A camera controller 100 receives information concerning theloading chamber cover status from a loading chamber cover status latch102. The controller also receives information concerning the presence ofa film cassette in the loading chamber from a presence sensor 104.Preferably, the presence sensor also provides an indication of the filmspeed, film type, and number of exposure frames of the film cassette.Such information can easily be provided, for example, by magneticallyencoded or optically encoded data placed on the exterior of the filmcassette. A camera user initiates making a frame exposure by pressing anexposure button 106, also referred to as the shutter button. In responseto the pressing, the controller 100 activates an exposure mechanism 108that includes the camera shutter, diaphragm, and (typically) anelectronic flash.

The camera controller 100 also controls the various release pins thatengage and disengage the indicator tab with the status windows. Asillustrated in FIG. 11, the controller so of the preferred embodimenthas control of an "unexposed film" release pin 110 and a "partiallyexposed film" release pin 112. The camera optionally may have control ofa "fully exposed film" release pin 114. More particularly, the cameracontroller has knowledge of the number of exposures on the film cassetteand whether the film cassette is loaded and the chamber cover closed,and keeps track of the number of exposures initiated by the user throughthe exposure button 106. In this way, the controller determines theexposure status of the film and also determines which release pins mightappropriately be extended or retracted.

Thus, when the first fame of the film cassette is exposed, thecontroller 100 extends the "unexposed film" release pin 110 so that theindicator tab can move from the unexposed icon 28a that it initiallyindicated to the next indicating window. In the case of a non-MRIcamera, the partially exposed icon 28b is not used and therefore thecontroller in a non-MRI camera would always extend the "partiallyexposed film" release pin 112. Altenatively, the non-MRI camera couldhave a spring-loaded release pin such as illustrated in FIG. 5,simplifying the controller operation.

As noted above in connection with the tab changing schemes, after thefirst frame of the film cassette is exposed in an MRI-equipped camera,the controller 100 can automatically change the indicated exposurestatus from the initial unexposed status to the partially exposedstatus. The controller achieves this by activating the "unexposed film"release pin 110. In this way, if the camera user invokes the MRIfeature, the indicator tab is in the correct position and does not haveto be moved. The alternative tab changing scheme descried above involvesthe controller 100 activating both the "unexposed film" release pin 110and the "partially exposed film" release pin 112 to permit the indicatortab to move to the fully exposed status window. Thereafter, if the MRIfeature is invoked then the controller activates the otherwise optional"fully exposed film" release pin 114 to permit the indicator tab to backup as the film is rewound and engage the partially exposed film statuswindow.

Under the first tab changing scheme described above, only twocontrollable release pins 110, 112 are needed but under the second tabchanging scheme, three controllable release pins 110, 112, 114 areneeded. This is because, under the first tab changing scheme, theindicator tab never has to move from the filly exposed film positionback to the partially exposed film position. The indicator tab simplymoves forward by one status window as the exposure status a changes. Incontrast, under the second tab changing scheme, the indicator tab mustpotentially move from the fully exposed film position back to thepartially exposed film position and then to the fully exposed position.

If the MRI camera implements the first described tab changing scheme,then when the controller 100 exposes the last frame of the filmcassette, the controller causes the "partially exposed film" release pin112 to be extended. This permits the indicator tab to move as thecontroller advances the film, thereby moving the indicator tab into thecorresponding film status window. It should be understood that when thecamera user has taken the filly exposed film cassette to a filmprocessor, the film processor will develop the film and leave it in thefilm cassette with the indicator tab extending into the processedrelease pin window. Proper indication of the processed status can beimplemented by placing the film cassette in an appropriate cassettehandling mechanism. The exact nature of the mechanism can take manyforms, which will occur to those skilled in the art. For example, thefilm processor could load the film cassette into a processor apparatusand control a "processed film" release pin that permits movement of thetab into the last indicator window for indicating the fully processedcondition. It should be apparent that there is no need for the camera toinclude such a release pin. Preferably, the film exposure status also isdetected by the camera from the film cassette or is indicated on anexternal film cassette encoding mechanism detectable by the camera.

FIG. 12 is a flow diagram that presents the processing steps followed bythe camera controller of the preferred embodiment in controlling theactuation of the moveable release pins. At the start of the release pinactuation determining process, the controller checks to see if the filmmovement to be initiated by a pressing of the shutter button will resultin a change to the film exposure status, as indicated by the decisionbox numbered 202. If the film movement will not result in a change tothe film exposure status, then the controller does not need to move anyrelease pins, as indicated by the flow diagram box numbered 204. Thecontroller processing then moves the film, as indicated by the flowdiagram box numbered 206, and continues (at box 207) to await the nextshutter button activation and start the checking for a film statuschange at the decision box numbered 202.

If the film movement will result in a change to the film exposurestatus, an affirmative outcome at the decision box numbered 202, thenthe controller will next determine what the new film status is, asindicated by the flow diagram box numbered 208. For example, asdescribed above, when the camera receives a fresh cassette, this stepcomprises determining whether the status upon loading will change from"unexposed film" to "partially exposed film" or "fully exposed film".The new status will depend on the MRI or non-MRI capability of thecamera and on the tab changing scheme employed.

If the camera receives a cassette with a "partially exposed film"status, this step (flow diagram box 208) comprises the cameradetermining the next available unused frame and advancing the film tothat predetermined point. The camera will then determine if the statuswill change from partially exposed to fully exposed or will remainunchanged, in accordance with the number of frames remaining in thecassette. Generally, the status determination occurs upon pressing ofthe shutter button. Thus, at the last frame of a film cassette, it mightbe necessary to move the film forward sufficiently to change theindicated status from "partially exposed film" to "fully exposed film",in accordance with the tab changing scheme.

After the new film status is determined, the film controller will causethe release pin for the current status to be extended, as represented bythe flow diagram box numbered 210. This action permits the indicator tabto engage the next (appropriate) film status window. It should beunderstood that the movable release pins can be biased to remainextended at all times or can be biased to remain retracted, as desired.Solenoid actuation, for example, could provide the pin action thatpermits indicator tab movement. The processed film icon 28d will neverbe used by a camera and therefore the release pin corresponding to theprocessed film window can, if desired, be provided with a spring loadingso that it always is extended into the window.

Assuming the film exposure status has changed and the appropriaterelease pin for the new status has been retracted, the controller movesthe film in the film cassette, as represented by the flow diagram boxnumbered 206. Movement of the film causes rotation of the driver diskand flex disk, thereby moving the indicator tab to the appropriatewindow where the retracted release pin permits the indicator tab tobecome engaged. Processing then, once again, returns to the start of theroutine where the controller waits for the next change in film status.As noted above, if there is no change in film exposure status, then noneof the release pins are extended and the driver disk rotatesindependently of the flex disk, keeping the indicated film exposurestatus constant.

Thus, the film cassette described above includes a driver disk coupleddirectly to the cassette film spool and a flex disk with an indicatortab whose position relative to a window of the film cassette indicatesthe film exposure status. The cassette is advantageously used with acamera that changes the position of the indicator tab when the filmspool is rotated upon film movement by engaging the flex disk and thedriver disk. The film status indicator tab otherwise does not engage thedriver disk and does not change position. Thus, the exposure status ofthe film is visually indicated by the film cassette without complicatedfilm park mechanisms. An MRI-equipped camera has at least one movableindicator release pin that moves the flex disk into and out ofengagement with the drive disk and thereby selectively changes theposition of the indicator tab. A camera controller determines the filmstatus and controls the movement of the indicator release pin to changethe position of the film status indicator tab in accordance with thefilm status. A non-MRI camera simply changes the film status fromunexposed to fully exposed. Thus, the film cassette of the preferredembodiment can be used advantageously with both MRI-capable cameras andnon-MRI cameras.

The present invention has been described above in terms of a presentlypreferred embodiment so that an understanding of the present inventioncan be conveyed. There are, however many configurations for visual filmexposure indicating systems not specifically described herein, but withwhich the present invention is applicable. The present invention shouldtherefore not be seen as limited to the particular embodiment describedherein, but rather, it should be understood that the present inventionhas wide applicability with respect to visual film exposure indicatingsystems generally. All modification, variations, or equivalentarrangements that are within the scope of the attached claims thereforeshould be considered within the scope of the invention.

The following elements and their corresponding reference numerals areused in the drawings:

camera film cassette combination 10

camera 12

viewfinder 14

objective lens 16

electronic flash 18

loading chamber cover 20

loading chamber 22

film cassette 24

end plate 26

film exposure status icons 28

unexposed film icon 28a

partially exposed film icon 28b

fully exposed film icon 28c

processed film icon 28d

status indicator window 30

indicator tab 32

film spool 34

mechanical status window 36

photographic film 38

cassette body 39

driver disk 40

flex disk 42

drive socket 44

idler socket 45

film spool ledge 46

locating key 48

flex disk feature 49

drive pin 50

driver feature 52

release pin 60

spring 61

idler pin 62

film driving pin 64

solenoid actuator 74

camera controller 100

loading chamber cover status latch 102

film presence sensor 104

exposure button 106

exposure mechanism 108

unexposed film release pin 110

partially exposed film release pin 112

fully exposed film release pin 114

We claim:
 1. A film cassette for use with a photographic camera inmaking exposures, the film cassette comprising:a cassette body having aplurality of film status windows; a film spool, contained within thecassette body, onto which is wound an elongated strip of film that ismoved within the camera as exposures are made; a driver disk that isdirectly coupled to the film spool; a flex disk that can be urged intoand out of engagement with the driver disk such that the flex diskrotates with the driver disk only when engaged with it; and a filmstatus indicator whose position relative to the film status windowsindicates the status of the film; wherein movement of the film spoolwhen the flex disk is engaged with the driver disk causes the flex diskto move and the position of the film status indicator relative to atleast one of the film status windows to change, and movement of the filmspool when the flex disk is not engaged with the driver disk causes nochange in the relative position of the film status indicator.
 2. A filmcassette as defined in claim 1, wherein:the flex disk includes a driverpin that can be coupled with the driver disk, thereby engaging the flexdisk with the driver disk; the film status indicator comprises anindicator pin on the flex disk that projects toward the film statuswindows, such that the indicator pin extends into a film status windowand thereby indicates the status of the film and moves with the flexdisk such that the indicator pin can be pressed out of a film statuswindow and thereby couple the flex disk with the driver disk.
 3. A filmcassette as defined in claim 2, wherein the indicator pin is located ona surface of the flex disk directly opposite the driver pin.
 4. A filmcassette as defined in claim 1, wherein the film status indicatorcomprises a projection that extends outwardly from the flex disk suchthat the projection extends into a selected one of the film statuswindows to thereby indicate the film status associated with the filmstatus window and can be moved from a current window through which theindicator extends to a next window only when the film status indicatoris depressed from out of the current window.
 5. A film cassette asdefined in claim 4, wherein the film status indicator projection ispressed out of the current film exposure starts window by a release pinof the camera with which the film cassette is used.
 6. A film cassettecomprising:a generally cylindrical container defining a cassette bodyhaving a volume; an end plate that covers one end of the cassette bodyand includes a plurality of film exposure status notches that representthe film status as being one of either an unexposed, exposed, orprocessed condition; a film spool, rotatably supported in the cassettebody, on which an elongated roll of film can be wound such thatunwinding the film causes the film spool to rotate; a driver diskcoupled directly to the film spool such that the driver disk rotates inresponse to rotation of the film spool, the driver disk further having adriver feature; a flex disk that can be urged into and out of engagementwith the driver disk such that the flex disk rotates with the driverdisk only when engaged with it; an indicator tab that can be moved intoand out of engagement with one of the film exposure stats notches whenthe flex disk is rotated such that moving the indicator tab intoengagement with one of the film exposure status notches urges the flexdisk out of engagement with the driver disk and thereby halts rotationof the flex disk, thereby indicating the film status as being thecondition represented by the film exposure status notch with which theindicator tab is engaged, and moving the indicator tab out of engagementurges the flex disk into engagement with the driver disk.
 7. A filmcassette as defined in claim 6, wherein the flex disk further includes adrive pin that engages the drive feature when the indicator tab ispressed out of engagement with one of the film exposure status notchesand releases the drive feature when the indicator tab is engaged withone of the film exposure status notches to thereby permit the driverdisk to rotate independently of the flex disk when the film spool isrotated.
 8. A film cassette as defined in claim 6, wherein the filmexposure status notches of the end plate represent the film status asbeing one of either an unexposed, partially exposed, fully exposed, orprocessed condition.
 9. A film cassette as defined in claim 7,wherein:the driver feature of the driver disk comprises acircumferential projection; and the flex disk is axially located betweenthe driver disk and the end plate, the drive pin comprises a pin thatprojects toward the driver disk, and the indicator tab projects towardthe end plate such that the drive pin makes contact with the driverfeature of the driver disk when the indicator tab is pressed out ofengagement with the film exposure status notches and the driver disk isrotated, thereby rotating the flex disk with the driver disk.
 10. A filmcassette as defined in claim 9, wherein the indicator tab is located ona surface of the flex disk directly opposite the drive pin.
 11. Aphotographic camera comprising:a camera body that receives a roll offilm that is advanced as frames of the film are exposed; a loadingchamber in the camera body that receives a film cassette having a filmexposure status indicator; a loading chamber cover that moves to openthe loading chamber and permit the film cassette to be received therein;a movable indicator release that engages the film cassette and changesthe status of the film exposure status indicator; and a controller thatdetermines the film status and controls the movement of the movableindicator release to selectively change the status of the film exposurestatus indicator in accordance with the determined film status.
 12. Aphotographic camera as defined in claim 11, wherein:the movableindicator release comprises a plurality of pins that can be selectivelymoved to extend into any one of a plurality of film exposure statuswindows of the film cassette; and the controller moves the pincorresponding to the determined film status during a film movement intothe selected film exposure status window, thereby changing the status ofthe film exposure status indicator, and does not move any otherindicator release pin.
 13. A photographic camera as defined in claim 12,wherein each pin extends into a different film exposure status indicatorwindow of the film cassette when moved by the controller.
 14. Aphotographic camera as defined in claim 13, wherein the movableindicator release pins are coupled to the loading chamber cover.
 15. Aphotographic camera as defined in claim 11, wherein the movableindicator release changes the status of the film exposure statusindicators to indicate the film status as being in either an unexposed,partially exposed, fully exposed, or processed condition.
 16. Aphotographic camera comprising:a camera body; a loading chamber in thecamera body that receives a film cassette having a roll of film that ismoved as frames of the film are exposed and further having a pluralityof film exposure status indicators that indicate the film status asbeing in one of a plurality of conditions; a loading chamber cover thatmoves to open the loading chamber and permit the film cassette to bereceived; at least one indicator release pin that moves to engage thefilm cassette and change the condition of the film exposure statusindicators when the roll of film is moved; and a controller thatdetermines the film status and controls the advancement of the roll offilm and the movement of the indicator release pin to engage the filmcassette and thereby change the status of the film exposure statusindicators in accordance with the determined film status.
 17. Aphotographic camera as defined in claim 16, wherein:the camera includesa plurality of indicator release pins such that a separate pin isprovided for each film exposure status indicator of the film cassette;and the controller moves only the indicator release pins necessary toindicate the determined film status and does not move any otherindicator release pins.
 18. A photographic camera as defined in claim16, wherein the camera includes an indicator release pin that permitschanging the condition of an "unexposed film" exposure status indicatorand a "partially exposed film" exposure status indicator.
 19. Aphotographic camera as defined in claim 16, wherein:the film exposurestatus indicators comprise a plurality of status windows in thecassette, each of which receives an indicator pin that thereby indicatesthe film exposure status as corresponding to the receiving statuswindow; and each indicator release pin engages a different status windowwhen moved by the controller.
 20. A photographic camera as defined inclaim 16, wherein the movable indicator release pins are coupled to theloading chamber cover.
 21. A photographic camera as defined in claim 16,wherein the movable indicator release pins correspond to status windowsrepresenting one of either an unexposed, partially exposed, fullyexposed, or processed condition.
 22. A photographic combinationcomprising:a film cassette havinga cassette body having a plurality offilm status windows, a film spool, contained within the cassette body,onto which is wound an elongated strip of film, a driver disk that isdirectly coupled to the film spool; an indicator flex disk having a filmstatus indicator whose position relative to the film status windowsIndicates the status of the film, wherein the flex disk can be engagedand disengaged with the driver disk such that movement of the film spoolwhen the flex disk is engaged with the driver disk causes the positionof the film status indicator relative to at least one of the film statuswindows to change and such that movement of the film spool otherwisecauses no change in the relative position of the film status indicator,and a photographic camera havinga camera body, a loading chamber in thecamera body that receives the film cassette, a loading chamber coverthat moves to open the loading chamber and permit the film cassette tobe received therein, a movable indicator release that engages the filmcassette and changes the status of the film status indicator relative tothe film status windows, and a camera controller that causes filmexposures to be made as the film in the cassette is moved, determinesthe film status, and controls the movement of the movable indicatorrelease to selectively change the status of the film status indicator inaccordance with the film status.
 23. A photographic combination asdefined in claim 22, wherein the camera controller provides a mid-rollinterrupt function that automatically rewinds the film into the filmcassette for cassette removal and then, upon loading the film cassetteback into the loading chamber, automatically moves the film to the nextavailable unexposed frame.
 24. A method of operating a camera toindicate the film exposure status of a film cassette having a movableindicator tab that is moved to a cassette film status window thatindicates the film exposure status, which changes as the film is movedin the camera, the method comprising the steps of:providing a movablecamera release pin for each film status window from which the indicatortab will be moved; determining what the film exposure status will beafter a pending film movement is completed; moving an indicator tabrelease pin corresponding to the current film exposure status if thefilm exposure status will be changed after the pending film movement iscompleted and maintaining all movable release pins in their presentposition if the film exposure status is not changed; and completing thefilm movement and automatically simultaneously changing the indicatedfilm status.
 25. A method as defined in claim 24, further including thesteps of:receiving a film cassette containing photographic film andhaving a film status window and indicator tab condition that indicates astatus of "unexposed film"; and advancing the film to an initial frameposition and changing the condition of the film status window andindicator tab to indicate a status of "partially exposed film".
 26. Amethod as defined in claim 25, further including the steps of: invokinga mid-roll interrupt feature; andrewinding the film to a predeterminedposition to permit removal of the film cassette from the camera withoutexposing the film.
 27. A method as defined in claim 26, furtherincluding the steps of:receiving a film cassette containing photographicfilm and having a film status window and indicator tab condition thatindicates a status of "partially exposed film"; and advancing the filmto a last exposed frame position without changing the condition of thefilm status window and indicator tab.
 28. A method as defined in claim24, further including the steps of:receiving a film cassette containingphotographic film and having a film status window and indicator tabcondition that indicates a status of "unexposed film"; and advancing thefilm to an initial frame position and changing the condition of the filmstatus window and indicator tab to indicate a status of "fully exposedfilm".
 29. A method as defined in claim 28, further including the stepsof:invoking a mid-roll interrupt feature; and rewinding the film to apredetermined position to permit removal of the film cassette from thecamera without exposing the film and changing the condition of the filmstats window and indicator tab to indicate a status of "partiallyexposed film".
 30. A method as defined in claim 29, further includingthe steps of:receiving a film cassette containing photographic film andhaving a film status window and indicator tab condition is thatindicates a status of "partially exposed film"; and advancing the filmto a last exposed frame position and changing the condition of the filmstatus window and indicator tab to indicate a status of "fully exposedfilm". .Iadd.
 31. A film cassette comprising:a cassette body having afilm status window; a film spool contained within the cassette body; adriver disk that is directly coupled to the film spool; a flex disk thatcan be engaged and not engaged with the driver disk such that the flexdisk rotates with the driver disk only when engaged with it; and a filmstatus indicator whose position relative to the film status windowindicates the status of film; wherein movement of the film when the flexdisk is engaged with the driver disk causes the flex disk to move andthe position of the film status indicator relative to the film statuswindow to change, and movement of the film spool when the flex disk isnot engaged with the driver disk causes no change in the relativeposition of the film status indicator. .Iaddend..Iadd.32. A filmcassette comprising: a generally cylindrical container defining acassette body having a volume; an end plate that covers one end of thecassette body and includes a film exposure status notch that representsthe film status as being an exposed condition; a film spool, rotatablysupported in the cassette body, on which an elongated roll of film canbe wound such that unwinding the film causes the film spool to rotate; adriver disk coupled directly to the film spool such that the driver diskrotates in response to rotation of the film spool, the driver diskfurther having a driver feature; a flex disk that can be engaged and notengaged with the driver disk such that the flex disk rotates with thedriver disk only when engaged with it; and an indicator tab that can bemoved into and out of engagement with the film exposure status notchwhen the flex disk is rotated such that moving the indicator tab intoengagement with the film exposure status notch urges the flex disk outof engagement with the driver disk and thereby halts rotation of theflex disk and indicates an exposed condition. .Iaddend.